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Agronomy and Crop Sciences

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South Dakota State University

Electronic Theses and Dissertations

Sunflower

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Full-Text Articles in Life Sciences

Evaluating Fungicide Timing, Efficacy, And Sensitivity As Well As Candidate Resistance Genes Against Fungi Causing Phomopsis Stem Canker In Sunflower, Ruchika Kashyap Jan 2022

Evaluating Fungicide Timing, Efficacy, And Sensitivity As Well As Candidate Resistance Genes Against Fungi Causing Phomopsis Stem Canker In Sunflower, Ruchika Kashyap

Electronic Theses and Dissertations

Phomopsis stem canker is one of the major diseases of sunflower (Helianthus annuus L.) caused by complex of Diaporthe spp., in the U.S. This disease became of economic importance after 2010 epidemic in Minnesota, North Dakota, and South Dakota and since then the prevalence of this diseases has increased due to increased average precipitation in these major sunflower growing regions of the U.S. The two important disease management strategies involve the use of fungicides and partially resistant hybrids. However, over the years, researchers and growers have seen varied results on Phomopsis stem canker disease severity reduction and yield gains, when …


Phomopsis Stem Canker Of Sunflower (Helianthus Annuus L.): Etiology And Epidemiological Conditions Affecting Endophytic Population Of Diaporthe Spp., And Fungicide Efficacy, Nabin Kumar Dangal Jan 2022

Phomopsis Stem Canker Of Sunflower (Helianthus Annuus L.): Etiology And Epidemiological Conditions Affecting Endophytic Population Of Diaporthe Spp., And Fungicide Efficacy, Nabin Kumar Dangal

Electronic Theses and Dissertations

Phomopsis stem canker (PSC), caused by species of Diaporthe, is a major disease of sunflower (Helianthus annuus L.) in the U.S., which can cause yield loss over 40%. The disease prevalence increased since 2010 in the major sunflower producing U.S. states of Nebraska, Minnesota, North Dakota, and South Dakota. Previous studies on the use of foliar fungicides in managing Phomopsis stem canker indicated mixed results on their efficacy in disease reduction and yield gain. Additionally, we do not have sufficient information on asymptomatic colonization by endophytic Diaporthe on sunflower tissue and how foliar fungicide and weather parameters affect the prevalence …


Insecticidal Seed And In-Furrow Treatment Recommendations For Soybean And Sunflower, Brady Hauswedell Jan 2018

Insecticidal Seed And In-Furrow Treatment Recommendations For Soybean And Sunflower, Brady Hauswedell

Electronic Theses and Dissertations

Throughout the 2016 and 2017 growing season, field research experiments were replicated across South Dakota. Many times seed treatments are used prophylactic, which is neither good for the producers or the environment. Producers will be able to reduce production costs, if they only use a seed treatment when necessary. The purpose of the first experiment was to determine the effects of seed treatments in combination with planting date and seeding rate on soybean yield. To determine the effects, two years of field data from four eastern South Dakota locations were compared. Within each year and location we compared two planting …